1 /* SPDX-License-Identifier: GPL-2.0+ OR BSD-3-Clause */
2 /* ******************************************************************
3  * debug
4  * Part of FSE library
5  * Copyright (c) Meta Platforms, Inc. and affiliates.
6  *
7  * You can contact the author at :
8  * - Source repository : https://github.com/Cyan4973/FiniteStateEntropy
9  *
10  * This source code is licensed under both the BSD-style license (found in the
11  * LICENSE file in the root directory of this source tree) and the GPLv2 (found
12  * in the COPYING file in the root directory of this source tree).
13  * You may select, at your option, one of the above-listed licenses.
14 ****************************************************************** */
15 
16 
17 /*
18  * The purpose of this header is to enable debug functions.
19  * They regroup assert(), DEBUGLOG() and RAWLOG() for run-time,
20  * and DEBUG_STATIC_ASSERT() for compile-time.
21  *
22  * By default, DEBUGLEVEL==0, which means run-time debug is disabled.
23  *
24  * Level 1 enables assert() only.
25  * Starting level 2, traces can be generated and pushed to stderr.
26  * The higher the level, the more verbose the traces.
27  *
28  * It's possible to dynamically adjust level using variable g_debug_level,
29  * which is only declared if DEBUGLEVEL>=2,
30  * and is a global variable, not multi-thread protected (use with care)
31  */
32 
33 #ifndef DEBUG_H_12987983217
34 #define DEBUG_H_12987983217
35 
36 
37 /* static assert is triggered at compile time, leaving no runtime artefact.
38  * static assert only works with compile-time constants.
39  * Also, this variant can only be used inside a function. */
40 #define DEBUG_STATIC_ASSERT(c) (void)sizeof(char[(c) ? 1 : -1])
41 
42 
43 /* DEBUGLEVEL is expected to be defined externally,
44  * typically through compiler command line.
45  * Value must be a number. */
46 #ifndef DEBUGLEVEL
47 #  define DEBUGLEVEL 0
48 #endif
49 
50 
51 /* recommended values for DEBUGLEVEL :
52  * 0 : release mode, no debug, all run-time checks disabled
53  * 1 : enables assert() only, no display
54  * 2 : reserved, for currently active debug path
55  * 3 : events once per object lifetime (CCtx, CDict, etc.)
56  * 4 : events once per frame
57  * 5 : events once per block
58  * 6 : events once per sequence (verbose)
59  * 7+: events at every position (*very* verbose)
60  *
61  * It's generally inconvenient to output traces > 5.
62  * In which case, it's possible to selectively trigger high verbosity levels
63  * by modifying g_debug_level.
64  */
65 
66 #if (DEBUGLEVEL>=1)
67 #  define ZSTD_DEPS_NEED_ASSERT
68 #  include "zstd_deps.h"
69 #else
70 #  ifndef assert   /* assert may be already defined, due to prior #include <assert.h> */
71 #    define assert(condition) ((void)0)   /* disable assert (default) */
72 #  endif
73 #endif
74 
75 #if (DEBUGLEVEL>=2)
76 #  define ZSTD_DEPS_NEED_IO
77 #  include "zstd_deps.h"
78 extern int g_debuglevel; /* the variable is only declared,
79                             it actually lives in debug.c,
80                             and is shared by the whole process.
81                             It's not thread-safe.
82                             It's useful when enabling very verbose levels
83                             on selective conditions (such as position in src) */
84 
85 #  define RAWLOG(l, ...)                   \
86     do {                                   \
87         if (l<=g_debuglevel) {             \
88             ZSTD_DEBUG_PRINT(__VA_ARGS__); \
89         }                                  \
90     } while (0)
91 
92 #define STRINGIFY(x) #x
93 #define TOSTRING(x) STRINGIFY(x)
94 #define LINE_AS_STRING TOSTRING(__LINE__)
95 
96 #  define DEBUGLOG(l, ...)                               \
97     do {                                                 \
98         if (l<=g_debuglevel) {                           \
99             ZSTD_DEBUG_PRINT(__FILE__ ":" LINE_AS_STRING ": " __VA_ARGS__); \
100             ZSTD_DEBUG_PRINT(" \n");                     \
101         }                                                \
102     } while (0)
103 #else
104 #  define RAWLOG(l, ...)   do { } while (0)    /* disabled */
105 #  define DEBUGLOG(l, ...) do { } while (0)    /* disabled */
106 #endif
107 
108 #endif /* DEBUG_H_12987983217 */
109